Conventionally known as one type of gas engine are gas engines that use gases such as 6C gas and 6B gas, which contain a comparatively large proportion of hydrogen components, and that use pure hydrogen as a fuel.
FIG. 13 is a block diagram that shows an overall configuration of a power generating system that generates power with this type of gas engine. As the diagram shows, in this gas engine, an output shaft 131a that extends from an engine unit 131 is connected to a power generating device 132, and power is generated by the power generating device 132 using the rotational driving force of the output shaft 131a. 
Furthermore, the air intake system of the gas engine contains an air supply system and a fuel supply system. A gaseous mixture of air supplied from the air supply system and fuel supplied from the fuel supply system is supplied to the combustion chamber so that the engine unit 131 is able to drive.
The air supply system is provided with a supercharger (compressor) 133 and an intercooler 134. Air is compressed by the supercharger 133, then this air is cooled by the intercooler 134, enabling high density air to be supplied to the combustion chamber. It should be noted that the supercharger c is directly coupled to an output shaft 136a of a turbine 136 provided at an exhaust tube 135 through which exhaust gas passes, and compresses air with the rotational output of the turbine 136.
This gaseous mixture of air supplied from the air supply system and fuel (hydrocarbon-based fuels, pure hydrogen, etc.) supplied from the fuel supply system is supplied to the combustion chamber, and power is generated by the power generating device 132 driven by the engine unit 131.
However, this type of gas engine has the following problems, and sufficient practicability is yet to be achieved.    (1) Backfiring occurs easily because the combustion velocity inside the combustion chamber is high.    (2) Knocking occurs easily because the methane number of the fuel is low.    (3) The high rate of heat generation invites reduced thermal efficiency of the engine.
The inventors of the present invention studied the causes of these drawbacks, and they found the presence of hydrogen components in fuels to be a cause of these drawbacks.
In consideration of these points, the object of the present invention is to present a gas engine that can prevent backfiring and knocking, and can improve engine thermal efficiency.